This invention belongs to the field of agricultural chemistry and relates to herbicides and plant fungicides. Herbicides and fungicides have become the basis of an enormous industry, and are commonly used in the culture of virtually every crop and ornamental plant. It has been abundantly proved that the proper use of herbicides, for the elimination of weeds which consume water and nutrients and shade the crop from the sun, and fungicides for the control of plant pathogens, is necessary to maximize production. Such agricultural chemicals, properly used, produce benefits, both in yield and in economic profit, which far outweigh the expense of the chemicals.
The 1,3,4-thiadiazol-2-ylureas have been the subject of research in agricultural chemistry. Some compounds of the group have been found to be herbicidal. For example, Driscoll, German Offenlegungsschrift No. 2,017,842, disclosed thiadiazolylureas having a vast assortment of 5-substituents including cyanoalkylthio substituents. Metzger, Belgian Pat. No. 721,034, showed such compounds having alkyl, alkenyl, cycloalkyl and alkylthio 5-substituents. Hoegerle, Belgian Pat. No. 725,984, disclosed thiadiazolylureas having perfluoroalkyl 5-substituents and a variety of substituents on the urea nitrogens, including cyanoalkyl substituents.
References which discuss the herbicidal activity of the 1,3,4-thiadiazolylureas include Cebalo, South African Pat. No. 69/1559, concerning such compounds having a 5-acyclic hydrocarbon group, and Cebalo, U.S. Pat. No. 3,726,892, concerning 5-sulfamoyl compounds.